Method of operating blast furnaces



Dec. 9, 1924- S. B. SHELDON METHODOF OPERATING BLAST FURNACES Filed Sept. 20. 22

. 2 Sheets-Sheet 1 Dec. 9, 1924- Y 1 1,518,459

s. B. SHELDON ymmop 0F OPERATING ams'r FURNACES Filed Sept. 20 l922 2 Sheets-Sheet 2 Patented Dec. 9, 1924.

UNITED STATES SAMUEL B. SHELDON, OF DULUTH, MINNESOTA.

mnrrron or ornnarme BLAST FURNACES...

Application filed September 20, 1922. SerialNo. 589,440.

To all whom it'ma-g concern:

Be it known that I, SAMUEL B. SHELDON, a citizen of the United States, residing at Duluth, in the county of St. Louis and State of'Minnesota, have invented certain new and useful Improvements in Methods of Operating Blast Furnaces, of which the' following is a specification.

' bootlegs to a bustle pipe. According to.

This invention relates to a new and improved method of operating blast furnaces and-more s cifically to a method of applying the a1r blast to such'furnaces.

The blast furnace now in general use is provided with a plurality of 'tuyeres,

usually 10 or 12, which are connected by common practice, the air is introduced through all of the tuyeres simultaneously.

.From consideration of 'Bernouilis law of the flow of gases, itis manifest that the tuyeres more remote from the point where the main .air line joins the bustle pipe can never pass air into the furnace with the same velocity as tuyeres nearer the point of ingress of the air.

Further, it is found in actual practice that although the same amount and pressure of air may be supplied to tuyer'es continuously, the resultant pressure in the tuyere will differ from time to time. This is believed to be due to what is called in practice blast-wandering in the'furnace. A large portion of the blast follows a certain upward path through the *"furnace because at that particular time it is the path of least resistance. This will continue until some other path of lesser resistance is established. It is well known among furnace operators that during only relatively short periods of time is the entire cross-section of the hearth performing for uniform melting. This blast wandering and lack of uniformity induces slips, hangs and all the various detrimental phenomena encountered in blast furnace operation.

If it were possible to cause the point or points of ingress of the air into the fur- I nace to be held stationary while the furnace itself revolved, then every point in the circumference of the hearth would be sub -jected to the same conditions, in so far as air blasting and consequent combustion is concerned. Due to structural difiiculties inherent in present blast furnaces, such a course is obio'ously impractical. Substantially-"the same result can be obtained,

beat all times closed oii while the remainder tinuously throughout the process, addi tional tuyeres being progressively opened and others closed so that the zone of air 'the circumference of the furnace.

It is an additional object to provide a method of this character in which air is supplied to a portion only of the circumference of the furnace, the portion continuously changing throughout the process.

Itis an ad itional ob ect to provide a method of this character in which the zone of air blast, in effect, revolves about the furnace during operation.

Other and further objects will appear as the description proceeds.

I have illustrated in the accompan ing drawmgs portions of a blast furnace a aptedt-iilo permit the use of my invention there- W1 In the drawings Figure 1 is a vertical section through the lower portion of a blast furnace; and

Figure 2 is a somewhat diagrammatic plan view taken approximately on the line of tuyeres' of Figure 1.

Referring now to the drawings, the furnace 3 isprovided with the bustle pipe 4 from which the bootlegs 5 lead to the open, a greater quantity of air will pass throughtuyeres F and G than through tuyeres A and L which latter are most tant from the point of introduction of the air. Consequently there will be a permanent variation of the blast in the furnace. If the valves controlling tuyeres G to L are shut off, all air will enter through tuyeres A to F and the amount entering-through each tuyere will be increased. If then after a predetermined period of time, the valve controlling tuyere F is closedand that controlling tuyere L is open and after a further similar lapse of time the .valve controlling tuyere E is closed and that controlling tuyere K opened and this process is continued, the air blast will, in efiect, revolve around the periplhery of the hearth. The

blast will cover t e entire circumference, not simultaneously but at regular intervals All parts of the furnace will be subjected to the same regular irregularity and the effect will be substantially the same as if the a points of introduction of the air remained be constantly changing. This will result in stationary while the furnace revolved.

By controlling the air blast in this manner the roduction' of channels causing blast wan ering in the furnace will be minimized since the point of introduction of the air will a more unitorm operation and will reduce slips, hangs and other detrimental phenomena encountered in blast furnace operation, y

1. Themethod of blastfurnace operation c'omprisingthe application of the blast air through a portion only of the eriphery, the portion changin throughout the process.

2. The metho of blast furnace operation comprising the application ofthe blast air through a portion onlyof the periphery, the portion changing its location throughout the process but remaining substantially constant in amount. v

3. The method of blast furnace operation comprising'the application of the blast air through a portion only of the periphery,.the

portion progressing around the furnace during the process.

4;. The method of comprising the applicationv of the blast air through a portion only ofthe tuyeres, said .portion consisting of a plurality of adjacent V tuyeres and progressing around the eblast furnace operation riphery of the furnace during the operation thereof.

Signed .at Duluth, Minnesota, this 13th da of September 1922. l a V .Y sAirUEL SHELDON. 

